Targeted retail coupons influence category-level food purchases over 2-years

Abstract

Background: Targeted coupons strongly influence purchasing behavior and may represent an innovative approach for improving dietary behaviors.

Methods: The retail analytics firm, Dunnhumby, provided secondary retail data containing grocery transactions, targeted coupon exposures, and coupon use for 2500 households over 2-years. The USDA Quarterly At-Home Food Purchasing Database was used to categorize individual foods into 52 categories and combined into 12 food groups. Mixed effects linear models estimated the difference-in-difference effects of coupon exposure on category-level purchase rate/wk. pre- and post-campaign; models also tested effect modification by food category.

Results: Category-level food purchases significantly increased post-campaign. Mean (SD) food purchases/wk. Among exposed households (17.34 (13.08) units/wk) vs. unexposed households (3.75 (4.59) units/wk) were higher (p < 0.001). Difference-in-difference effects of coupon exposure showed a higher increase in purchase rate among exposed vs. unexposed households (5.73 vs. 0.67, p < 0.001). Food category significantly modified the association between coupon exposure and coupon campaign. Category-level purchase rate among exposed vs. unexposed households was relatively higher in less healthful (e.g. convenience foods) vs. more healthful categories (e.g. nuts) with a 1.17 unit/wk. increase in convenience foods purchase (p < 0.001) vs. a 0.03 unit/wk. increase in nuts (p < 0.001). Exploratory analyses suggested that price elasticity of food categories for targeted coupons (1.02-2.81) was higher than previous estimates for untargeted coupons.

Conclusion: Across food categories, coupon exposure increased category-level purchase rate, with a relatively larger effect size for less healthful than more healthful categories. Promising results from this preliminary study suggest that experimental research is warranted to determine whether targeting with the explicit purpose of improving dietary quality can more effectively influence diet, and whether it can do so more cost effectively.

Keywords: Dietary pattern; Difference-in-difference; Grocery purchases; Healthful food purchase; Incentives; Intervention; Longitudinal; Retail purchase quality; Targeted coupon.

Fig. 1

Effect of targeted coupons on purchase rate for all foods. Differences in mean food purchase rate per week pre- and post- a targeted coupon campaign among 2500 households exposed vs. unexposed to a targeted coupon campaign. Exposed households are represented with a solid line and unexposed households are represented with a dashed line. The pre-campaign period describes the period prior to the coupon campaign (day<=223); the post-campaign period describes the period after the coupon campaign began (223 < day< 642)

Fig. 2

Effect of targeted coupons on purchase rate for each food category. Figures are divided into two groups: less healthful foods and more healthful foods. Mean food purchases per week at food category level among exposed households vs. unexposed households pre- and post-campaign are shown through solid and dash lines. Exposed households are represented with a solid line and unexposed households are represented with a dashed line. The pre-campaign period describes the period prior to the coupon campaign (day<=223); the post-campaign period describes the period after the coupon campaign began (223 < day< 642)